It requires three amino acids--glycine, glutamic acid and cysteine--for development and can be found in nearly all body tissues
A highly cited 2020 umbrella meta-analysis of 37 randomized controlled trials concluded that L-carnitine supplementation provides a modest but significant reducing effect on body weight, body mass index (BMI), and fat mass
But for many people searching for alternatives, the real issue is cost or access to the brand-name product, making compounded tirzepatide the closest possible "alternative." Regulatory changes have complicated this landscape significantly
These properties make it a popular supplement for cognitive support, particularly in the context of age-related cognitive decline and neurodegenerative conditions
Overall, there is not sufficient evidence to recommend B12 on its own for the elderly with impaired cognitive function, although those with early symptoms may benefit